The present invention relates to a rigid hinged-lid packet.
More specifically, the present invention relates to a rigid hinged-lid packet made from a flat preweakened blank of cardboard or similar.
A particularly advantageous application of the present invention is in the manufacture of packets of cigarettes, to which specific reference is made in the following description purely by way of example.
Rigid hinged-lid packets of cigarettes are normally in the form of a rectangular-section parallelepipedon, and comprise a front and a rear wall connected to two lateral walls at respective sharp longitudinal edges.
Rigid packets of the above type, i.e. in the form of a rectangular-section parallelepipedon, have several drawbacks on account of their non-anatomical shape and their tendency to cause rapid wear of clothing fabrics or similar with which they may come into contact.
A further drawback of rectangular-section parallelepiped packets lies in their relatively high rigidity in the regions of the relatively small side walls and adjacent right-angle corners as opposed to the relatively poor rigidity of the front and rear walls, which are easily deformed inwards when the external transparent wrapping is applied and made to shrink about the packet.
Owing to the above, the cigarettes inside the packet, instead of assuming a low-energy distribution inside the packet (the distribution having the lowest possible energy would be a distribution over a circle), are maintained in an extremely high energy distribution with the result that, when the packet is first opened, the extraction of the first cigarette from the front row of the packet is always rather difficult.
All the above drawbacks were at least in part overcome by bevelled edge and rounded edge packets of the types disclosed in EP-A-0204933 and EP-A-0205766 respectively. However, in general, these two types of packet need, for being manufactured with a relatively high precision, the use of special machines, such as those disclosed in EP-A-0205894 and EP-A-0200087, which are relatively slow in operation and are absolutely dedicated machines, i.e. cannot be used for manufacturing packets other than the above two types of packet.
All the above renders the above two types of packet very expensive to manufacture.
Moreover, apart from being expensive, the rounded edge packets have the further drawbacks that, in general, their cover does not close in a precise manner on their box portion owing to the difficulty to make two rounded profiles to coincide with one another, and the external transparent wrapping does not suit the external shape of the packet at the rounded corners of its bottom and top surfaces with the result that, at these rounded corners, rigid outwardly protruding tips are formed which are not only anaesthetic, but also cause rapid wear of clothing fabrics or similar with which they may come into contact.
It is an object of the present invention to provide a rigid hinged-lid packet designed to eliminate the aforementioned drawbacks.
In particular, it is an object of the present invention to provide a rigid hinged-lid packet, which:
allows the relevant cigarette group to deform to a relatively low-energy distribution, thus making the extraction of the first cigarette from the packet easier;
avoids causing rapid wear of clothing fabrics or similar with which it may come into contact; and
may be manufactured in an economic, easy and fast manner by using packing machines which, apart for very minor modifications, are those which are used for manufacturing rectangular-section parallelepiped packets.
According to the present invention, there is provided a rigid hinged-lid packet substantially in the form of a rectangular parallelepipedon and comprising a front wall and a rear wall substantially parallel to each other, and two lateral walls parallel to each other and substantially perpendicular to said front wall and said rear wall; said front wall and said rear wall each being connected to each of said two lateral walls at a respective sharp edge; characterized in that said front wall and said rear wall each comprise a respective flat central portion, and two lateral bands preweakened by longitudinal weakening lines; each lateral band being curved with the concavity facing inwards to connect the relative central portion to the lateral wall at the relative said sharp edge.